of Terebratulina septentrionalis. 415 



for it was believed that the relations between them and the 

 Polyzoa, as urged by Agassiz, Milne-Edwards, Huxley, 

 Hancock, Dana, and others, would be verified when the deve- 

 lopment of the Brachiopoda was known. In this path of 

 inquiry the investigator will find an open field. 



For a long time I have been interested in the relations of 

 the class under consideration, and in an early paper, entitled 

 "Hgemal and Neural Regions of Brachiopoda"*, and later, 

 in a paper " on the Classification of Mollusca, based on the 

 Principle of Cephalization " fj urged the intimate relations 

 existing between the Brachiopoda and Polyzoa. With the 

 hope of learning something about the early stages of one of 

 our native species of Brachiopods, I visited Eastport, Maine, 

 in the early part of June 1869,' and this communication em- 

 braces a summary of the incomplete observations there made 

 — incomplete, as I was unable to secure any data on the em- 

 bryology of the species. At the outset my microscope proved 

 altogether inadequate to the work before me, though the mi- 

 nute size of the objects examined, coupled with the compli- 

 cated texture of the shell through which the soft parts had to 

 be observed, rendered the work at the best laborious and difii- 

 cult. In every case, however, the figures given in the accom- 

 panying plates are correct transcripts of the drawings made 

 from the animal : in no instance is there given any combina- 

 tion of several unfinished sketches to make a more intelligible 

 or perfect whole. This will explain the absence of detail and 

 completeness in many of the figures presented ; at the same 

 time it is believed that the outlines will be more valuable from 

 the fact that they are not schematic or composite. 



For a clear exposition of the organization of the Brachio- 

 poda, I would refer to the exhaustive memoir of Albany 

 Hancock above referred to — a memoir which justly merited 

 the honom' conferred upon him in the award of the Royal medal. 



On the Early Stages of Terebratulina septentrionalis, Cou~ 

 thouyX. — The specimens upon which the following examina- 

 tions were made were dredged in fifteen-fathoms water in 

 the harbour of Eastport, Maine, in the first week of June 

 1869. The species occurs in great numbers at various depths, 

 and has also been collected at low-tide mark, by Dr. Stimp- 



* Proc. Boston Soc. Nat. Hist. 1862, vol. ix. 



t Proc. Essex Instit. Salem, 1865, vol. ix. part 6. Also reprinted in 

 Amer. Journ. Sc, & Arts, 1866, vol. xlii. no. 124. 



X A brief resume of this paper was published in the ' American Natu- 

 ralist,' 1869, Sept. No. vol. lii. Since reprinted in Amer. Journ. Sc. and 

 Arts for Jan. 1870. 



The general results were communicated at the 18th Annual Meeting 

 of the American Association for the Advancement of Science, Aug. 1869. 



